Apparatus for wireless signaling.



IR. A. FESSENDEN. APPARATUS FOR WIRELESS SIGNALING.

APPLICATION FILED JAN. 6, 1906.

Patented Apr. 22, 1913.

3 SHEETS-11331 1.

-INVENTOR Atty WITNESSES R. A. FESSENDEN. I APPARATUS FOR WIRELESS SIGNALING.

I APPLICATION FILED JAN. 6, I906.

1,059,666. I Patented Apr. 22, 1913.

3 SHEETS-SHEET 2.

R. A.'PESSENDEN. APPARATUS FOR WIRELESS SIGNALING.

APPLICATION FILED JAN. 6, 1906.

Patented Apr. 22, 1913.

3 SHEETS-SHEET 3.

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my, a. (mm

STATES 10 I u a improvements in the art of prevent ng .-1n-

original application Med January 9, 1905, Serial No. 240,269. Divided and th'is ii, 1906. Serial No. 294,928.

PATENT oFF oE.

lineman) A. rns snmmn, or wasnmeron, msrnrc'r or coLmirBrA, assreno'n, BY rins ng assremmu'rs, .110 SAMUEL m. xmrunn, or PITTSBURGH, PENNSYL- VANIA, 1m) msny irfinannnu r, or BLOOMFIELD, NEW JERSEY, nncnrvnns.

arramrusron wmrinnss sIenALINe.

To all whom it may concern:

Be it known that I, REGINALD A. Fns- :sENDE N, residing at -Washingt'n, in the District of Columbia, ,a citizen of the United States, have invented or discovered cer tain new and useful Improvements in Ap-,

paratus for Wireless S1 aling, of which improvements the following is ,a specification. s I v The invention described herein relates to .terference with receipt of telegraphic signals' at a station whether such interference iscaused by atmospheric disturbance or by the generation of waves at other stations In the accompan 'ng drawings forming a part of this 'speci cat on, Figures 1 arid 7 are diagrammatic views illustrating receiving stations constructed in accordance with my improvementt'Fig. 2 is a detail View illustrating the .preferred form of transformer. Figs; 3 and 4 are plan and side elevation respectively, illustrating the prea desirable constructio'nb 'ferred' 'form of adjustable capacity. Fig. 5 illustrates" :another 'form of adjustable capacity. Fig. 6'shows 'in plan and elevation 8;is ajview'showing in detaila portion of the apparatusshowndn Fig. 7, and Fig. 9

showsa modification of the arrangement in Fig. -1,.as hereinafter described. v

In Fig. 1, 1 is i' reoeiving antenna, grounded at'4, 2 and 5 represent-inductances adjustable by ineansof the sliding contacts 3 and 6, 7 and 8 represent primaries and 9 and 10 secondariesof transformers, .11 and f 12. and 13 represent condensers, preferably adjustable. preferabl -other a in operative relation-tothe 'receiver 17. The circuit including the secondaries '9 Wind "-10 and the r'eceiver pre fer-- ably contain the variable inductance's 14 and :14; and theadjustable-"condensers 15; 16

and 18. l9 -is' an indicating mechanismvand 20 a potentiometer. 21 and 22 are capacitles -for'adjusting the capacity to "ground of a point on the receiving circuit','prefer,ably one of the terminals of there eiver, though both may be so connected, and preferably consisting o'f adjustable condensers connected to ground zit-23.

Specification of Letters Patent. I

transformer, Fig.

The secondaries!) and l0"'are arranged in series with each",

application filed January F igs.'2 an 6 show suitable forms of'trans' formers. secdndary, The primary may consist for example of 100 turnsof #18 copper wire Wound on a glass jar 25L, five inches in diamglass jar 25, six inches in diametei'. The inside of the glass jar 25 is preferably covstruction of transformers shown in Figs. 6'

resistance or inductance 27': may be laced in the circuit to ground when the shield is grounded.

Another form of transformer is shownin wo'un 1n the groove of one rin and'the secondary wound inthe groove 0 the-other ring. These rings may also be covered with metallic paint'origold-fo il or a metallic disk placed-"between the .two coils. Th s-{constructionis especially adapted forxuse where .it is desired to obtain largeinductance'with' small capacity. u r

plates 30-and 81, preferably semicircular or be made to overlap theother plate's more; or less as required. It is nreferredto secure mav be provided with an operating handle.

Patented A 22,1913.

In Fig..; 2, 7 is a primary and 9 a eter and the secondary may. consistof 3.5- turns of #532 D. 5. upwir'e wound ona T shown in Fig. 7. The shield for the conradially slit, as shown in F ig. 8, may -be The shaft has its axis coinciding with the ered; with a conducting material 26 .soar-v ranged as to shield the secondary fromelecand 7 is indicated at 50in Fig. 7.. IA high Fig; 6'where 28,' 29 are hard rubber rings havin grooves cut in them and the primary ,Figs. 3 and 4 show one form of variable condenser consisting of intercallatin-g metalapproximately so in contour. Alternate plates. are movable in and out between the other plates so that the one setof platesmay the movable plates-31 to agshaft 32 and it l inside the insulating tube, 35.

is arranged as on ,in which there is not any'inaterial overlapping of one set of plates bv the other. One set of plates is insulated from the other. A dial 34*and indicating finger 33 are so arranged that one or the other will be shifted with the movable plates.

Fig. 5 shows another form of variable" condenser, consisting of a tube 36 of conducting material, an insulating tube, 35, inside the conducting tube, 36, and a tube, 37,

The conducting tubes are arranged so that one maybe moved longitudinally of the other. A scale one of these tubes so as to indicate capacity in different relative positions of the tubes.

Both the primaries7 and 8 should have the same-number of turns anu both the secondaries 9 and 10 should have the same number of turns, these turns may be altered, as for example, ov the movable contacts 46 and 47, shown in Fig. 7. By sliding these contactsthe circuits may be timed by varying the inductances instead of by varying the capacity. The primary 7 and the secondary 9.? may also "be made movable relative to each other by sliding 7 along the graduated arm 48 so as to vary the mutual inductance between primaries and secondaries, as shownin Fig. 7. v

The circuits 1, 2, 8, 12, 5, 13, 4, and 1, 2, 7, 11,5, 13, 4, are tuned in such a way that when an impulse of the desired periodicity is received on the receivin conductor, it generates strong currentst rough one of these circuits, for example 1, 2, 8, 12,15,13, 4 but very weak cur-rents through the other and consequently, being wound in opposite directions the-receiver 17 is strongly affected; but said cir-' cuits are so tuned that-impulses which'have not the desired periodicity will divide evenly through both circuits and consequently produceequal and opposite efifects which being thus neutralized, produce no effect on the receiver. This is generally accomplishedempirically and I have found a'suitable method n als or'distu'rbances would be to turn the variable capacity 11 to the position of zero capacity and 'to then turn the variable capacity,'12, until the jmaximum efi'ect-is produced-b the waves it is desired to receive. The variable capacity, 11, is then turned until the interfering sigare cut out.

It may happen cannot be renderedquite 'com lete, on account of there being a phase difference inthe currents flowing through the two primaries,

and this ismore'espe'c' ally apt to happen with interference preventers in which two the secondaries 9 and 10 I that the neutralization.

transformers are used instead of; three or four transformers.

To order toinsure complete neutralization, a device which may be called a-- phase-correcter may be used, consisting of a circuit adapted togenerate a voltage equal and in opposite phase to the non-compensated volt age impressed upon the secondaries 9 and 10' I do not limit and opposite in direction. myself to any specific method of effecting this compensation, but a suitable method is shown in Fig. 1, where 38 and 39 are coils in inductive relation to each other and referably capable of being adjusted to different distances a art by sliding on the graduated arm 40. oil 38 is in series with the secondaries 9 and 10, (Fig. 1) and coil 39 is operatively connected to an adjustable inductance 41, and adjustable resistance 42. A current will therefore flow through the circuit 39, 41,

ablev inductance 41, which consists of two coils capable of relative angular movement or by changing the resistance 42 which is preferably of very small capacity. The in tensity of the voltage which would be impressed on the circuit containing the secondaries 9, l0 and the coil 38 may be varied by varying the position of the coil 39. In this way a voltage maybe impressed on the. circuit of the secondaries 9 and 10 which will have the proper phase and the proper value to neutrallze the unbalanced component I of the interfering signals or disturbances.

Many other ways Wlll suggest themselves of accomplishing this result. For example, the phase compensator may be inductively connected to the vertical instead 'of directly connected, as shown in Fig. 7

Alsoa variable capacity 49 may be substituted for the variable inductance 41 of Fig.

42, and the.phase of th1s,cur-. .ren't can'be altered by varying the adjust- 1, and as here shown, in Fig. 9, in which case a leading current will be obtained instead of a lagging one, and the winding of the coil 39 must be reversed. The connections of the coil 39 may be so arranged that they may be changed by-means of a switch shown at 43, according as the unbalanced component is a leading or lagging one.

It has'been experimentally demonstrated by the applicant that this apparatus for protecting a receiver from undesired efiects may without necessary change be employed in wire telegraphy, and the claims are to be understood as not hmited to signaling by electromagnetic waves. The method herein describedxis, claimed in my co-pending application Nd. 240,269 filed January 9th, 1905, of which application this one is a division.

I claim as my invention:

1. In wireless telegraphy, apparatus for preventing interference comprising two antenna-to-ground circuits, each containing the primary of a transformer, a receiver circuit said transformers, and a phase adjustingidecuit.

circuits, substantially as described.

2. Apparatus forwireless telegraphymom prising two antenna-t -ground circuits each containing the primary ofan adjustable vice connected to the said antenna-to-ground transformer, means for adjustingboth-the coupling-and the inductance in saidgtransformers, and separately groundedsecondary circuits connected to a receiver," substantially asdescribed. f,

3. In wireless telegraphy apparatus the combination'with an antenna-toground circuit containing a transformer, a secondary circuit inductively coupled to thefirst circuit epm e n i i a c.0 denser and a re'ceivenin the secondarycirwireless itelegraphyapparatus, the Y combination with an antennai-to-groiund. circuit, contain transformer,- o a secondary circuit containing a receiver grounded through a condenser and connectedto the first by a secondary, said antenna-to-ground circuit havingan- 8d .ditional inductance and all said inductances being ariable by single turns, substantially.

.as described;

-- 5. In a systemofwireless signaling; an

antenna, a transformer operatively connected there 0, and an electrostatic shield be-. tween t e primary' andgsecondary, of said transformer. A I -In testimony where0f, -I ha'v,e hereunto set- 5 my hand. REGINALD A; FESSENTDEN; Witnesses:

' DOROTHY O. THURMAN," Jnssm'EL BnN'r.

the'adjustable Pflmary of a 

